Centrifugally driven spin device

ABSTRACT

An apparatus for providing a continuous path along an axis in a chamber only when the chamber rotates about the axis. The apparatus includes a plurality of discs or members in the chamber, with each member having a path forming portion in approximately its center of floatation which, if the member is uniform, is the center of the disc. The members are stacked upon each other with the plane of each member being substantially perpendicular to the axis. The chamber has a cross sectional area measured perpendicular to the axis which is of a size to permit the members to align themselves to provide the continuous aperture about the axis when all of the members are in a predetermined position. There is additionally provided a fluid in the camber so that as the chamber is rotated about the axis, when there is fluid in the chamber, the member move to their predetermined positions, centering the center of floatation to yield the continuous path.

United States Patent 1 Egli et a1.

[ CENTRIFUGALLY DRIVEN SPIN DEVICE [75] Inventors: Werner H. Egli;Asbjorn M.

Severson, both of Minneapolis, Minn.

[73] Assignee: Honeywell Inc., Minneapolis, Minn.

[22] Filed: Dec. 13, 1971 [21] Appl. No.1 207,354

Primary Examiner-Samuel W. Engle Atmrnvy-Charles J. Ungemach, John S.Munday ct al.

[451 Aug. 7, 1973 [57] ABSTRACT An apparatus for providing a continuouspath along an axis in a chamber only when the chamber rotates about theaxis. The apparatus includes a plurality of discs or members in thechamber, with each member having a path forming portion in approximatelyits center of floatation which, if the member is uniform, is the centerof the disc. The members are stacked upon each other with the plane ofeach member being substantially perpendicular to the axis. The chamberhas a cross sectional area measured perpendicular to the axis which isof a size to permit the members to align themselves to provide thecontinuous aperture about the axis when all of the members are in apredetermined position. There is additionally provided a fluid in thecamber so that as the chamber is rotated about the axis, when there isfluid in the chamber, the member move to their predetermined positions,centering the center of floatation to yield the continuous path.

3 Clalms, 3 Drawing Figures PATENIEB AUG 7 I973 FIG.I

III/NI 1 CENTRIFUGALLY DRIVEN SPIN DEVICE BACKGROUND OF THE INVENTION Itis often times desirable to provide a device which is capable ofpermitting the transfer of a signal along an axis only under certainspecific conditions. In the production of artillery shells and othermunitions, fuses are employed which initiate the explosives containedtherein for firing at a predetermined time. Because of the highlyexplosive nature of artillery shells, it is desirable that the fuses beincapable of firing the shell at times other than the proper time duringuse.

It has become desirable to create some form of apparatus which providesa satisfactory block or impass which prevents ignition of the shellduring all times except after firing. Many such devices have beendesigned, some of which are expensive and/or intricate to manufacture.Other fuzes, while sound in principle, fail to provide the desiredreliability during mass production.

Some fuses which have been generally accepted and which describe thegeneral state of the art are set forth in U. S. Pat. Nos. 2,641,186,3,118,379 and 3,425,354.

SUMMARY OF THE INVENTION The present invention is seen to be asignificant advance in the state of the art. The apparatus describedherein is simple and relatively inexpansive to manufacture yet itprovides a perfectly safe method for arming an artillery shell afterfiring.

The present invention provides an arming and time delay mechanism forspin operated fuzes and other devices which rotate about an axis. Itsunique feature is that it employs a number of buoyant washer shapeddiscs which are randomly dispersed in a fluid housing. In the unarmedcondition, the discs prevent transmission between the detonator and thebooster since the various buoyant washer shaped discs are not centeredabout the axis to provide a path. The discs may be randomly dispersed,or they may be biased in a position prohibiting the formation of thecontinuous aperture. Activation of the device is caused by spin of thedevice about an axis. During spin, fluid is caused to flow into achamber containing the buoyant washer shaped discs. Inasmuch as thedensity of the fluid is at least on the average greater than that of thediscs or members, the lighter discs are centered such that their centerof floatation in the fluid is at the axis of spin. Thus, once sufficientflow has taken place to float the discs and center their center offloatation, a continuous aperture or path is provided.

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding ofthe present invention, reference is hereby made to the drawings, inwhich:

FIG. 1 is a cross sectional view of one embodiment of the invention;

FIG. 2 is a cross sectional view showing a second embodiment of thepresent invention; and

FIG. 3 is a cross sectional top view of the device shown in FIG. 2.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to FIG. 1, showing across section of the present invention, a chamber is provided andcontains a number of disc-like members 18, 20, 22, 24

and 26. These discs have a path forming portion proximate their centerof rotation, 19, 21, 23, 25 and 27. Normally the path forming portion ofthe member is a hole, and such path forming member will hereinafter bereferred to as such. However, this portion may be conductive toelectrical or optical signals, such as a conductive couple inserted in aplastic disc or a clear portion in an opaque disc. Such path formingportions are clearly within the scope of the present invention. All thatis needed is to have a portion of the member be suitable for passage ofa signal while the balance of the member prohibits passage of thatsignal. The entire device is centered about an axis A and, when in use,is rotated about this axis A. Also attached to the chamber 10 is areservoir 12 which is suitable for holding fluids contained in eitherthe chamber 10 or the reservoir 12 prior to use of the device. Along theaxis A is a source of signal 14 and a receiver of signal 16. Thesesignal sending and receiving means 14 and 16 can be anything whichtransmits a signal, such as for example, signal transmitting means 14can be a detonator while signal receiving means 16 can be a booster.Thus, when the detonator is activated, such as upon impact, a blast orcharge is fired from the detonator 14 and is impacted upon the booster16 which then causes explosion of the shell in which this fuse isincorporated. The discs 18, 20, 22, 24 and 26 have suitable holes attheir centerof floatation such that, when all of the discs are centered,the signal transmitted by the sender means 14 goes down through thecenter holes 19, 21, 23, 25 and 27 into the reservoir 12 and is receivedby the signal receiving means 16.

The discs themselves can take any shape which is desirable as long asthe hole or path forming portion is centered at the center offloatation. Moreover, the discs may be constrained in one or moredirections, so that floatation by the fluid will cause them to move in aspecific direction, seeking to locate the center of floatation at theaxis, thereby performing useful work. The specific center of floatationfor any given member can readily be determined. Normally, in a uniformregularly shaped disc this center will be at its geometric center. Inirregular shaped, some degree of visual experimentation may benecessary. Likewise, as fluids of extremely high orlow density areemployed or as the fluids density is significantly greater than thedensity of the disc, irregular shaped members may have different centersof floatation for different shaped chambers and different quantities offluidQ Depending upon the relative densities of the disc materials andthe liquids, and of the geometry of the chamber 10 and reservoir 12, afixed amount of fluid will be required in the chamber 10 in order tocentrifugally float and center the discs 18 through 26. If, as it isintended, the-device is to be used as a fuse in an artillery shell, thedevice will experience what is known as set back, a force due to thefiring of the shell. Set back will cause as much fluid as possible toflow through opening 15 into the reservoir 12. As the reservoir 12 andchamber 10 spin about axis A, fluid will flow through openings 30 and 31communicating between reservoir 12 and chamber 10. The amount of fluidwhich accumulates in the upper chamber 10 can, if viscosity and rotationare suitable, be a function of the angle through which the spinningprojectile has been rotated about the axis A. It can easily be seen thatall of the parts of the reservoir are closer to the axis of spin A thanis at least part of the chamber. Accordingly, when the apparatus is spunabout the axis A, the fluid will be transferred through ports orconnecting means 30 and 31 to the chamber 10. The density of the fluidand the size of the openings 30 and 31 will determine the number ofrevolutions necessary to permit the flow ofa sufficient quantity offluid into the chamber to permit floatation of the discs 18 through 26.For most munitions, 26 revolutions is deemed to be a safe distance awayfrom the firing for arming. At this time, the discs will float and aligntheir center holes after this number of revolutions. There will then bea clear path from the signal sending means 14 to the signal receivingmeans 16. Moreover, due to the spin of the device, the liquid will becentrifuged outward so that the central path along axis A will be dryand free of liquid.

The device of the present invention offers features which preventaccidental arming of the device prior to the proper number ofrevolutions as set forth above. Basically, the discs originally arerandomly oriented in the chamber. Moreover, the signal which is sent bythe signal means 14 should not be so strong as to be able to penetrateeven one of the discs. Thus, the centering of the disc elsewhere so asto block the path along the axis A will prevent activation of the signalreceiving means. By simple calculation, it can be shown that if thenumber of discs are sufficiently great, and if the hole is sufficientlysmall, the probability of all of the holes accidentally lining up topermit the formation of the continuous aperture along the axis isinsignificant and therefore impossible from a practical standpoint. Forexample, if the discs have a diameter D and are contained in a chamberhaving a diameter ND, and if the disc center hole diameter is ED, thenthe discs have an area in which they can move around in of: A 7/4 (N 1)D The area of the center is equal to A rr/4 E D. The chances of thecenter hole overlapping its position at the center of the device is: P AM which in turn equals E /(N I)? If there are M number of discs, thechances of them all centering sufficiently so that there is an opencentral path down through their central holes is: P [E /(N 1) ]M, whichin turn equals (E/N- 1). If for example purposes we choose values suchthat: E 0.15; N 1.5; and M 8; then the probability P equals (0.15/05) oris approximately l/200,000,000. This analysis is based upon theassumption that the discs move independent of one another.

Thus it can be seen that the device is safe in the following respects.First of all, if the liquid fill were to be omitted, or leak away, thedisc could not be floated and (within the l/200,000,000 probability)would not line up to permit detonation. Secondly, if it were somehowpossible for the discs all to be centered with the projectilenon-spinning, there would be some fluid in the center path which wouldblock transmission of the signal or detonation. Moreover, if theprojectile itself were to tumble or wobble in flight, the spin would notbe uniform about the axis and the discs would become disorganized, againpreventing the propagation of the detonator blast.

To further insure the safety of such a device, the embodiment shown inFIG. 2 may be employed. Specifically, an axis B is provided, about whichthe device spins. Chamber 40 and reservoir 42 are connected to spinabout this axis B. Signal generating means 44 is provided to pass asignal through aperture 45 connecting the chamber and reservoir 42 tosignal receiving means 46. Again 44 and 46 may be detonators andboosters in an artillery shell.

Discs 48, 50, 52 and 54 are provided within the chamber 40 and haveholes 49, 51, 53, and 55 respectively. By alignment of these holes aboutthe axis B, the signal transmitting path from signal transmitting means44 to signal receiving means 46 along axis B is clear. However, thediscs 48', 50, 52 and 54 are maintained in a position other thancentered by spring means 60, 62, 64 and 66. Thus each of the four discsare blocking passage along the axis B. As shown in FIG. 3, the chamber40 is centered about axis B and contains disc 48. The disc 48 has a hole49 at a center of floatation. However, the disc 48 is positioned byspring mounted to chamber 40 by rivet 61 so as to place the hole 49 at apoint other than the center axis B. However, during rotation in thedirection shown by arrow 75, the spring 60 will be forced away from thedisc 48 and floatation of the disc 48 in the chamber 40 will permitalignment of the hole 49 about axis B, since the hole is centered at thecenter of floatation of the disc 48.

Thus, upon spin, the device in FIG. 2 will permit relaxation of springs60, 62, 64 and 66, allowing holes 49, 51, 53 and 55 to be centered aboutaxis B.

Thus it can be seen that the apparatus of the present invention issuitable for providing a safe condition wherein which transmitting meansis incapable of transmitting a signal to receiving means except undercertain specified conditions, namely sufficient spin to properly floatthe disc-like members to align the holes at their center of floatation.While this device has been described as being useful in a spin activatedfuze for armament shells, it is equally useful in other applications.For example, such a device could be adapted to rotate about its axisduring rotation of a drive shaft to permit free passage of the signalthrough the aperture only when the drive shaft would be in operation.

Having thus described the invention, what is claimed 1. An apparatus forproviding a continuous path along an axis in a chamber substantiallyonly when said chamber is caused to rotate about the axis, comprising:

a plurality of members in said chamber, each member having a pathforming a portion approximate to its center of floatation, each memberbeing substantially perpendicular to the axis;

said chamber having a cross sectional area perpendicular to said axis ofa size topermit members aligning to provide a continuous path about saidaxis when all of said members are in a predetermined position in theirplanes;

means defining a reservoir, said reservoir being positioned adjacent tosaid chamber such that all parts of said reservoir are closer to saidaxis than is at least a part of said chamber; means connecting saidreservoir to said chamber for providing a continuous path along saidaxis;

means connecting said reservoir to said chamber for permitting flow offluid, said fluid flow means being adapted to permit flow of a knownquantity of fluid from said reservoir to said chamber during a knownnumber of revolutions; and

a fluid in said reservoir, said fluid being capable of flowing throughsaid fluid flow means during rotation about said axis and havingsufficient density to move said members to the predetermined position.

6 2. The apparatus of claim 1 wherein said members a position differentfrom its predetermined position, are of ubstannauy f member said biasmeans being further adapted to release said density being less than saidfluid density. h

member upon rotation of said chamber about said axis.

3. The apparatus of claim 1 which further includes bias means forlocating at least one of said members at 5

1. An apparatus for providing a continuous path along an axis in achamber substantially only when said chamber is caused to rotate aboutthe axis, comprising: a plurality of members in said chamber, eachmember having a path forming a portion approximate to its center offloatation, each member being substantially perpendicular to the axis;said chamber having a cross sectional area perpendicular to said axis ofa size to permit members aligning to provide a continuous path aboutsaid axis when all of said members are in a predetermined position intheir planes; means defining a reservoir, said reservoir beingpositioned adjacent to said chamber such that all parts of saidreservoir are closer to said axis than is at least a part of saidchamber; means connecting said reservoir to said chamber for providing acontinuous path along said axis; means connecting said reservoir to saidchamber for permitting flow of fluid, said fluid flow means beingadapted to permit flow of a known quantity of fluid from said reservoirto said chamber during a known number of revolutions; and a fluid insaid reservoir, said fluid being capable of flowing through said fluidflow means during rotation about said axis and having sufficient densityto move said members to the predetermined position.
 2. The apparatus ofclaim 1 wherein said members are all of substantially the same density,said member density being less than said fluid density.
 3. The apparatusof claim 1 which further includes bias means for locating at least oneof said members at a position different from its predetermined position,said bias means being further adapted to release said member uponrotation of said chamber about said axis.